Small Basic: Control Statements

Small Basic: Control Statements

In the Microsoft Small Basic programming language, there are five types of control statements -
If statement, Goto statement, While loop statement,
For loop statement, and subroutine call statement. These statements build up with only fourteen keywords of
Small Basic. This article is an overview of these control statements. Control statements change program flow respectively.

Table of Contents

If statement

If statement or If clause is for making conditional branch. If you'd like to show "AM" or "PM" by checking clock, following code and chart are for that. There is another keyword "ElseIf" for this clause. For detail about "ElseIf",
see the next section.

' Start

hour =
Clock.Hour ' Get hour

If
hour < 12 Then ' hour < 12?

TextWindow.WriteLine("AM") '
Yes: Write "AM"

Else

TextWindow.WriteLine("PM") '
No: Write "PM"

EndIf

' End

Goto statement

Goto statement can jump anywhere labeled place in the program. Label is written with colon such as "start:". Following sample program checks input text, and if it is "Y" or "N" then shows "True" or "False", otherwise input text again with Goto statement
in line 10.

1.' Start

2.start:

3.TextWindow.Write("1+1=2
Y/N? ") ' Write "1+1=2 Y/N? "

4.ans = TextWindow.Read()
' Read ans

5.If
ans = "Y" Then ' ans?

6.TextWindow.WriteLine("True") '
"Y": Write "True"

7.ElseIf
ans = "N" Then

8.TextWindow.WriteLine("False")
' "N": Write "False"

9.Else

10.Goto
start ' other: input again

11.EndIf

12.' End

While loop statement

While loop statement repeats statements while condition is true. In following case, while condition "i <= 10" is true, "n = n + 1" and "i = i + 2" are repeated.

' Start

n =
0

i =
2

While
i <=
10

n
= n + i

i
= i + 2

EndWhile

TextWindow.WriteLine(n) '
Write n

' End

For loop statement

For loop statement repeats statements with increasing or decreasing a variable. In following case, statement "n = n + i" is repeated with increasing a variable "i" from 2 to 10 by inclement 2. And this sample shows same
result with the sample above.